Trait-based scaling of temperature-dependent foliar respiration in a species-rich tropical forest canopy

The scarcity of empirical data on leaf respiration (R) and its temperature sensitivity (e.g., Q10, defined as the proportional increase in R per 10°C warming) causes uncertainty in current estimates of net primary productivity of tropical forests. We measured temperature response curves of R on 123 upper-canopy leaves of 28 species of trees and lianas from a tropical forest in Panama, and analyzed variations in R and Q10 in relation to other leaf functional traits. Respiration rates per leaf area at 25°C (RA) varied widely among species and were significantly higher in trees than in lianas. RA was best predicted by a multiple regression model containing leaf phosphorus concentration, photosynthetic capacity, and leaf mass per area (r2 = 0.64). The mean Q10 value (2.4) was significantly higher than the commonly assumed value of 2.0. Q10 was best predicted by the combination of leaf carbohydrate concentration and growth form (trees vs lianas) (r2 = 0.26). The nighttime leaf respiratory ca...